Injection spray gun with adjustable pressure limitation

ABSTRACT

An injection spray gun with a holder comprising: a sheathing adapted to receive a cylindrical ampule; a handle fastened to the gun; an actuating lever pivotally attached to the handle; a plunger guided in the holder and connected with the actuating lever; a piston located in the cylindrical ampule wherein movement of the plunger causes forward thrust of the piston; and a pressure limiting device being provided for acting on at least one of the actuating lever and/or the plunger.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an injection spray gun with a holder configuredfor the attachment of a sheathing provided to receive a cylindricalampule, a handle connected therewith, an actuating lever attachedpivotally thereto and a plunger, guided in the holder and connected withthe actuating lever, causing the forward thrust of a piston located inthe cylindrical ampule.

2. Discussion of the Prior Art

Such injection spray guns are used for various medical purposes,especially by dentists for intraligamental anesthesia. The advantage ofsuch a spray gun is that it can produce a very high pressure for eachindividual spray process.

However the drawback with such injection spray guns is that the doctorusing the instrument must control and limit the pressure which isproduced purely by touch, in order to prevent the breaking open of thecylindrical ampule which is being used (containing the solution which isto be sprayed) and the washing of a tooth, to be treated, out of itsparadontal tooth socket (alveolar cavity) or at least its being workedloose.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to construct aninjection spray gun in such a manner that the pressure exerted by thelever mechanism on the fluid to be sprayed can be limited and evenadjusted and controlled.

This object is attained in that with an injection spray gun of thistype, a pressure limiting device is provided on actuating lever and/orplunger.

According to the invention, this pressure limiting device consistsessentially of a spring element and a two-arm shift lever.

It is advantageous that the actuating lever be fastened to the handle bythe two-arm shift lever, and the two-arm shift lever be mountedpivotally on an axis arranged in the handle. The actuating lever withits pivot axis is fastened pivotally on the first arm of the shift leverand the spring element operatively engages the second arm of the shiftlever.

With this arrangement, the shift lever acts as a block for the actuatinglever, and this block can deflect the pressure originated by theactuating lever when it has attained a certain level and upon release ofthis pressure can return to its original position. The spring elementforms the adjustable block force.

It is advantageous that the spring element be configured as a helicalspring and arranged on a guide rod. This guide rod is mounted flexiblyor by articulation with its first end on the second arm of the shiftlever and its second end projects into an adjusting screw installed inthe handle. One end of the spring element engages the rim of theadjusting screw.

This prescribed combination of spring element and guide rod allowsprecise adjustability of the block pressure caused by the springelement.

BRIEF DESCRIPTION OF THE DRAWING

The invention may be better understood by referring to the detaileddescription of the invention when taken in conjunction with theaccompanying drawings in which:

The sole FIGURE shows a partially cut open side view of an injectionspray gun according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The injection spray gun shown in the drawing consists essentially of ahandle 1, a holder 2 configured in one piece with the handle, and anactuating lever 3, mounted pivotally in the handle, which actuates apawl 4 through a lever mechanism built into the handle and explained inmore detail hereinafter, which engages sequentially in driving arms 6formed on plunger 5 and causes the advance of plunger 5 following anyactuation of actuating lever 3. Plunger 5 is guided in holder 2 and alsoin an additional guide member 7 on handle 1.

A sheathing 8 is introduced into holder 2, in which is also inserted apiston 10 closing the cylindrical ampule 9 containing the medication tobe sprayed in from the outside. The sheathing-like end of plunger 5comes into engagement on piston 10 and presses the piston into acylindrical ampule 9 during the spraying process.

Actuating lever 3 is mounted pivotally with its pivot axis 11 notdirectly in handle 1, but on the first arm 12 of a two-arm shift lever13, which in turn is fastened pivotally in handlle 1 around an axis 14.The top end 16 of a guide rod 17 is pivotally fastened about axis 18 tosecond arm 15 of the two-arm shift lever 13. The bottom end 19 of guiderod 17 projects into an adjusting screw 20 configured as a hollow body,which in turn is adjustable lengthwise in handle 1.

A helical spring element 21 is arranged on guide rod 17, with its bottomend 22 coming into contact with the rim 23 of adjusting screw 20 andwith its top end 24 engaging on a sheathing 25 arranged on guide rod 17.

The operation of the lever mechanism is as follows:

The doctor making use of the injection gun for an injection movesactuating lever 3 against handle 1, and actuating lever 3 pivots aroundpivot axis 11 and moves pawl 4 together with plunger 5 against piston10.

The pivot axis or pivot point 11 of actuating lever 3 on shift lever 13,stabilized by the force of spring element 21, forms the block, whichnonetheless withdraws from actuating lever 3 with a force exceeding theforce of spring element 21. The shift lever 13 is therefore pivotedaround its mounting axis 14 in handle 1 and guide rod 17 is sunkpartially into the hollow body of the adjusting screw 20, and as aresult of this shift of bearing point 11, actuating lever 3 can bepressed down as far as the mechanical stop of guide rod 17 in adjustingscrew 20, without increasing the injection pressure.

When actuating lever 3 is presssed down entirely and shift lever 13 isdeflected, spring element 21 assumes the injection until pivot point 11is pressed back into original position.

This pressure controlled lever mechanism guarantees on the one hand thatbursting of the cylindrical ampule on account of on exceedingly highpressure is no longer possible, and on the other hand, that paradontalteeth cannot be loosened and/or removed from their tooth socket by theintraligamental injection.

What is claimed is:
 1. An injection spray gun with a holder configuredfor attachment of a sheathing provided to receive a cylindrical ampulecontaining a piston comprising: a handle fastened to said holder; anactuating lever pivotally attached to said handle; a plunger guided insaid holder and connected with said actuating lever so that when thesheathing is attached to said holder, movement of said plunger causesforward thrust of the piston; and a pressure limiting device connectedfor acting on at least one of said actuating lever and said plunger. 2.An injection spray gun as defined in claim 1, wherein said pressurelimiting device comprises a spring element having a top and bottom endand a two-arm shift lever which has a first arm and a second arm.
 3. Aninjection spray gun as defined in claim 2, wherein said actuating leveris fastened to said handle with interposition of said two-arm shiftlever, and said two-arm shift lever is pivotally mounted on a transverseaxis arranged in said handle, said actuating lever being pivotallyfastened on said first arm of said shift lever; and said spring elementengages said second arm of said shift lever.
 4. An injection spray gunas defined in claim 3, wherein said spring element comprises a helicalspring;and said gun further comprises a guide rod having a first andsecond end and an adjusting screw having a rim; said helical springbeing arranged on said guide rod, and said guide rod being mountedflexibly with said first end on said second arm of said shift lever andwith said second end of said guide rod projecting into said adjustingscrew which is introduced into said handle and said bottom end of saidspring element engages on said rim of said adjusting screw.
 5. Aninjection spray gun with a holder comprising: a cylindrical ampule; asheathing having said cylindrical ampule disposed therein; a handlefastened to said holder; an actuating lever pivotally attached to saidhandle; a plunger guided in said holder and connected with saidactuating lever; a piston located in said cylindrical ampule whereinmovement of said plunger causes forward thrust of said piston; and apressure limiting device being provided for acting on at least one ofsaid actuating lever and said plunger.
 6. An injection spray gun asdefined in claim 5, wherein said pressure limiting device comprises aspring element having a top and bottom end and a two-arm shift leverwhich has a first arm and a second arm.
 7. An injection spray gun asdefined in claim 6, wherein said actuating lever is fastened to saidhandle with interposition of said two-arm shift lever, and said two-armshift lever is pivotally mounted on a transverse axis arranged in saidhandle, said actuating lever being pivotally fastened on said first armof said shift lever; and said spring element engages said second arm ofsaid shift lever.
 8. An injection spray gun as defined in claim 7,wherein said spring element comprises a helical spring;and said gunfurther comprise a guide rod having a first and second end and anadjusting screw having a rim; said helical spring being arranged on saidguide rod, and said guide rod being mounted flexibly with said first endon said second arm of said shift lever and with said second end of saidguide rod projecting into said adjusting screw which is introduced intosaid handle and said bottom end of said spring element engages on saidrim of said adjusting screw.
 9. An injection spray gun with a holderconfigured for attachment of a sheathing provided to receive acylindrical ampule containing a piston comprising: a handle fastened tosaid holder; an actuating lever pivotally attached to said handle andextending outside said handle and said holder; a plunger guided in saidholder and connected with said actuating lever so that when thesheathing is attached to said holder, movement of said plunger causesforward thrust of the piston; and a pressure limiting device connectedfor acting on at least one of said actuating lever and said plunger. 10.An injection spray gun as defined in claim 9, wherein said pressurelimiting device comprises a spring element having a top and bottom endand a two-arm shift lever which has a first arm and a second arm.
 11. Aninjection spray gun as defined in claim 10, wherein said actuating leveris fastened to said handle with interposition of said two-arm shiftlever, and said two-arm shift lever is pivotally mounted on a transverseaxis arranged in said handle, said actuating lever being pivotallyfastened on said first arm of said shift lever; and said spring elementengages said second arm of said shift lever.
 12. An injection spray gunas defined in claim 11, wherein said spring element comprises a helicalspring;and said gun further comprises a guide rod having a first andsecond end and an adjusting screw having a rim; said helical springbeing arranged on said guide rod, and said guide rod being mountedflexibly with said first end on said second arm of said shift lever andwith said second end of said guide rod projecting into said adjustingscrew which is introduced into said handle and said bottom end of saidspring element engages on said rim of said adjusting screw.
 13. Aninjection spray gun with a holder comprising: a cylindrical ampule; asheathing having said cylindrical ampule disposed therein; a handlefastened to said holder; an actuating lever pivotally attached to saidhandle and extending outside said handle and said holder; a plungerguided in said holder and connected with said actuating lever; a pistonlocated in said cylindrical ampule wherein movement of said plungercauses forward thrust of said piston; and a pressure limiting devicebeing provided for acting on at least one of said actuating lever andsaid plunger.
 14. An injection spray gun as defined in claim 13, whereinsaid pressure limiting device comprises a spring element having a topand bottom end and a two-arm shift lever which has a first arm and asecond arm.
 15. An injection spray gun as defined in claim 14, whereinsaid actuating lever is fastened to said handle with interposition ofsaid two-arm shift lever, and said two-arm shift lever is pivotallymounted on a transverse axis arranged in said handle, said actuatinglever being pivotally fastened on said first arm of said shift lever;and said spring element engages said second arm of said shift lever. 16.An injection spray gun as defined in claim 15, wherein said springelement comprises a helical spring;and said gun further comprises aguide rod having a first and second end and an adjusting screw having arim; said helical spring being arranged on said guide rod, and saidguide rod being mounted flexibly with said first end on said second armof said shift lever and with said second end of said guide rodprojecting into said adjusting screw which is introduced into saidhandle and said bottom end of said spring element engages on said rim ofsaid adjusting screw.